In conventional exposure apparatuses, the space between a projection optical system and a semiconductor wafer is typically filled up with high-cleanliness air or high-purity inert gas, such as nitrogen or helium. On the other hand, liquid immersion exposure apparatuses are known, which use a method for filling the space with liquid (liquid immersion medium) (see, for example, Japanese Patent Laid-Open No. 6-124873, International Publication No. 99/049504, and Japanese Patent Laid-Open No. 10-303114), However, technology has yet to be found that pays attention to addressing a case wherein a sequence of the liquid immersion exposure is interrupted.
In the case of a local-filling-method liquid immersion exposure apparatus in which a liquid immersion medium is locally supplied immediately beneath a projection optical system, the liquid-supply position for the liquid immersion medium and the position of an exposure-target chip (or exposure-target area) should accurately coincide with each other. If a sequence stop occurs during the stage being driven, it may be possible that liquid supply is implemented somewhere off the wafer. In such a case as this, the liquid immersion medium cannot be recovered with a recovery nozzle, whereby water leakage occurs. In order to restore the apparatus to its original condition, wiping and drying works for the leaked liquid immersion medium or replacement of electrical components is required. Such a restoration operation would reduce the availability of the exposure apparatus, and even the productivity of the device. Moreover, if a liquid immersion medium accumulates in a liquid-supply pipeline or a supply nozzle, contamination or dripping on the stage, of the liquid immersion medium, becomes a concern. When the trouble has been solved and the exposure is restarted, if liquid supply is started as it is, air and the liquid immersion medium that have accumulated in the pipeline intermingle with each other, thereby generating foam that may adversely affect the exposure.